Seasonal Variation and Source Apportionment of PM2.5 bound Water-Soluble Inorganic Ions (WSII) in Tier 2 and 3 Non-Attainment cities of India using PMF 5.0

The air quality in the Indian subcontinent has been a growing concern in recent years, with particulate matter (PM) being one of the major pollutants. PM_2.5, in particular, has a significant impact on human health and the environment as it can penetrate deep into the respiratory system. PM_2.5 has been linked to several health issues including respiratory and cardiovascular disease, while Water-Soluble inorganic Ions (WSII) contribute to the acidity and salinity of the air. In this study, we aim to investigate the seasonal variation and contributing sources of PM_2.5 and 9 associated WSII (Na+, NH⁴⁺, K⁺, Mg²⁺, Ca²⁺, F^-, Cl⁻, NO₃⁻ and SO₄²⁻) in two non-attainment Indian cities, Alwar and Amritsar in the states of Rajasthan and Punjab respectively. The study regions are selected owing to the unique meteorological conditions, population density and industrial activities. The study employs a combination of field measurements and comparative analysis to understand the sources and seasonal patterns of PM_2.5 and WSII in these cities. Initial analysis of PM_2.5 winter samples shows Nitrate (22.078 μg/m³) and Sulphate (17.408 μg/m³) to be the dominant anionic species and Ammonium (13.046 μg/m³) and Sodium (5.452 μg/m³) to be dominant cationic species for both day and night respectively in Alwar city. The total average day anionic concentrations for the same period were observed to be 31.37 μg/m³ and night concentrations to be 52.52 μg/m³ with total observed average day cationic concentrations to be 15.23 μg/m³ and night concentrations to be 23.29μg/m³.

This study provides valuable insights into the seasonal patterns of PM_2.5 and WSII and help understand the contributing factors and sources. This information can be used by policymakers to develop strategies for mitigating air pollution and improving the air quality in the region.